Governor



May 18, 192.6. 1,584,813

F. SCHMIDT GOVERNOR Filed Sept 23 1925 ,le as H 0R Sch midi: WITNESSES: I INVENTOR ATTORNEY 0 as the square Patented May 18, 192%.

iss su HENRY F. SCHMIDT, 0F LANSDOXVNE, PENNSYLVANIA, ASE-EGNOR TO \VESTINGHOUSE ELECTRIC MANUFACTURING COMEAN Y, A CDEIEOBATION OF PENNSYLVANIA.

Govnnnon.

Application filed September My invention relates to governing apparatus'for prime movers, more particularly for prime movers driving pumps which displace fluid by reason of the kinetic energy of their moving parts, and it has for its ob- I iect the provision of apparatus of the character designated which shall be effective to cause the pump to deliver a variable volume of fluid at substantially a constant pressure and at the same time prevent overspeeding of the prime mover.

Apparatus embodying features of my invention is illustrated in the accompanying drawings forming a part of this specification in which Fig. 1 is a view in elevation of a turbine driving a centrifugal pump and con= trolled by my improved governing apparatus and Fig. 2 is a diagrammatic view explanatory of the operation of my invention.

It is well known that, in the operation of rotary fluid pumps which displace fluid by reason of the kinetic energy of their moving vanes, such as centrifugal or propeller type,

pumps, the volume discharged by the pump through an orifice of constant area increases directly with the speed. It has also been determined that, for a given rate of fluid displacement and within certain limits, the pressure developed by the pump varies of the speed thereof. If the area of the orifice through which the pump is discharging be increased, the volume displaced by the pump for a given rate of speed is increased and the pressure is decreased. So long however as the increased orifice through which the pump is discharging is constant, the pressure developed by the pump varies as the square of the speed. If tie pump is discharging into a flu1d supply system wherein there is a variable demand for fluid from the system, the variable demand on the system acts as a variable of the discharge orifice of the pump and the pressure for a given speed varies as the volume demanded to a certain degree.

In many such systems there is required fluid at a substantially constant pressure regardless of the volume demand. In order to furnish a substantially constant pressure with a variable volume demand, it has been found necessary to provide a pump of relatively large capacity and to control the speed of the driving means th refor by a governor responsive to the pressure of the fluid delivered. by 'the pump, with added speed re- 23, 1925'. Serial No. 58,035.

sponsive mechanism to control the driving means beyond a given speed thereof. l/Vhere this method has not been resorted to, it has been customary to provide a storage reservoir having sufticient elevation to provide the desired pressure and maintain the reservoir full. In any event, to meet a constant-pre sure, variable-volume demand, the apparatus required therefor has heretofore been cumbersome and complicated.

In accordance with my invention I provide a fluid pressure operated governor for thedriving means of a rotary pump and furnish fluid for the operation of the governor at a pressure which is a function of the speed of the rotating shaft of the pump and of the volume demand by the system. Fluid pressure for the operation of the governor is furnished directly by an impeller type pump which develops a pressure varying as the square of the speed thereof. The pressure delivered by the impeller pump however is the sum of the pressure developed thereby and the pressure of fluid supplied it at its inlet. Fluid under pressure for supplying the impeller pump inlet is conveyed thereto from the delivery side of the bump supplying the fluid system.

Inasmuch as the pressure developed by the pump supplying the system is a function of the volume displaced thereby at a given speed, the pressure at the inlet of the impeller pump is a function of the volume demand on the system. The resultant pressure delivered by the impeller pump to the governor is therefore such thatthe driving means for the pump is controlled at a speed such as to cause the pump to furnish the fluid system with a constant pressure while supplying a variable volume demand of fluid within reasonable limits. Should there be an unusual demand upon the pump supplying the system such, for example, as when abrealr occurs in the line and the pressure developed by the supplying pump should drop an unusual amount, the driving means speeds up until the impeller pump alone dovelops suiiicient pressure to control the driving means before an unsafe speed is reached.

Referring now to the drawing for a better understanding of my invent-ion, I show at 10 a rotary pump, for example, a centrifugal pump, for supplying fluid under pressure to a system indicated diagrannnatically in Fig. 2 at 11,. wherein there is-avariable volume demand for fluid under pressure. The centrifugal pump 10 is driven by a turbine 13 through a coupling 12. The turbine 15 has a motive fluid inlet 13 and an exhaust outlet 11-. The admissimi ot motive fluid to the turbine through the inlet 13 is through an adn'iission valve 16 which is controlled by a fluid-presure-operated governor 17. The fluid-pressure-operated governor 17 may be of conventional type embodying a piston 18 biased in one direct-ion by a spring 19 and moved in the opposite direction by fluid under pressure.

Fluid pressure for operating the governor 17 is developed by an impeller type pump 21 driven directly by the turbine 15 and delivering fluid pressure to the governor 17 through a conduit 22.

Inasmuch as the fluid pressure delivered by the pump 21 to the {governor 17 is a tunetion of the speed of the pump and is the resultant of the speeg} oi the pump and of the pressure supplied to its inlet. it follows that the pressure delivered by the pump 21 to the governor 17 may be varied by the pressure from an outside source provided it at its inlet. I accordingly connect the inlet side of the pump 21, as at 23, to the discharge side of the pump 10, as at 2 1, and vary the pressure for operating the gov ernor 17 in accordance with the speed of the turbine 15 and. the pressure supplied by the pump 10. The turbine 15 must accordingly be capable of a comparatively wide speed range, as it is required to run it. at a speed for driving the pump 1 so that. the pump 10 will deliver a constant pressure of fluid, within reasonable limits. into the system 11 regardless of the volume demand.

The operation of apparatus made in ac cordance with my invention is as follows: Assume first that the turbine 15 is running and that there is no demand for fluid from the system 11. The pressure developed by the pump 10 is that required for the system 11 and is delivered to the intake side of the pump 21 and from thence delivered at a higher pressure to the governor 17. The pressure delivered to the governor 17 act ing against the piston 18 thereoi forces said piston downwardly and the valve 16 in a closing direction, holding the turbine at the speed necessary to develop the required pressure in the system 11. Should there be a demand for fluid from the system 11, the pressure developed by the pump 10, at the speed just assumed, is reduced and the pressure delivered to the intake side of the pump 21 likewise reduced. he pressure dc livered to the intake side-21 being reduced. the pressure delivered to the governor 17 is reduced. and the si-Jring 19 acts to force the piston 18 upwardly, opening the valve 16 a sufiicient amount to cause t'lieturbine 15 and the pump 1-0to-increase in speed to provide the required pressure in the system 11. Upon adecrease in demand tor fluid from the system 11, the pressure delivered to the intake side of the pump 21 increases. Upon an increase of pressure supplied to the intake side of the pump 21. the pressure delivered to the governor 17 by said pump increases and the piston 15 is moved downwardly by the increase in pressure. as previously described. slowing the turbine 15 down to the required speed.

Should there be an unusual demand for fluid from the system 11. causing an unusual decrease in pressure delivered by the pump 10. the pressure delivered to the pump 21 and to the governor 17 for a given speed decreases and the speed of the turbine is :wcordingly increased. As the speed ol the turbine 15 increases, the pressure developed by the pump 21 increases and, alter attaiir ing a certain speed regardless of the pressure at the pump intake, develops sufficient pressure to overcome the load on the spring 19 and holds the turbine to a speed within sate limits.

From the foregoing it will be apparent that I have devised an improved controlling means for a prime mover driving a fluid supply pump which is efl'ective to cause the prime mover to drive the pump at such a speed as to provide a constant pressure of fluid with a variable volume demand upon the fluid system.

ll'hile I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited. but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire. therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are spe j'ilically set truth in the appended claims.

hat I claim is:

1. The combination 01 a pump 'l'or providing fluid under pressure for a variable volume fluid system. a prime mover for driving the pump, a fluid pressure operated governor for controlling the prime mover. and means for developing fluid pressure for operating the governor which a function of the speed oi the prime mover and the pressure-of fluid developed by the pump.

52. The combination of a centrifugal pump for providing fluid under pressure for a varialgile volume fluid supply system, a turbine having an admission valve for driving the pump, a fluid pressure operated governor for controlling the admission valve. an impeller pump driven by the turbine lor sup plying fluid pressure to the governor. and conduit means leading from the delivery side of the centrifugal pump to the intake side of the. impeller pump.

The combination with a prime mover,

of a fluid pressure operated governor for controlling the prime mover, a rotary pump driven by the turbine for supplying; fluid pressure for operating; the governor, a second rotary pump for supplying fluid pressure for a fluid supply system, and conduit means for supplying the first mentioned rotary pump at its intake with fluid from the delivery side of the second rotary pump.

l. The combination With a pump deliver- .ing a variable volume of fluid under pressure to a fluid supply system, of a prime mover for driving the pump, energy controlling means for the prime mover, a fluid pressure operated governor for the energy controlling mleans, means for developing fluid pressure varying as a function of the speed of the prime mover plus the initial pressure supplied to said means for operating the governor, and means for supplying the fluid pressure developing means with fluid from the supply system.

In testimony whereof, I have hereunto subscribed my name this eleventh day of September 1925.

HENRY F. SCHMIDT. 

